We have previously reported the symptom benefit of calcium channel blocker therapy in patients with microvascular angina (chest pain, normal coronary angiograms, coronary microvascular constrictor response to ergonovine). In order to assess the impact of calcium channel blockers on left ventricular function, we administered diltiazem, verapamil, nifedipine, or nicardipine to 11 normotensive patients with abnormal rest and/or exercise left ventricular function (as assessed off all medications) by radionuclide angiography, and repeated studies after 3 months of calcium channel blockers. Calcium channel blocker therapy was associated with significant improvement in global and regional left ventricular responses to exercise. We conclude that calcium channel blockers benefit left ventricular function of patients with microvascular angina and evidence for inducible myocardial ischemia, probably by improving coronary flow dynamics during exercise stress.